As of October 2007, more than 1.6 million US military personnel had been deployed to conflicts in Afghanistan and Iraq. Research continues to document the injuries and mental health problems associated with service in these conflicts, which include posttraumatic stress disorder (PTSD), major depression, and traumatic brain injuries (TBI). This application seeks funding to perform analyses on, and disseminate results from, existing longitudinal data from more than 1000 individuals previously deployed to these conflicts. The baseline sample was recruited using geographically-targeted, random digit dialing, and captures a wide-range of individual characteristics, including all branches of service. The baseline sample includes more than 300 respondents who had probable PTSD or major depression, and more than 400 who experienced a probable TBI during deployment. Follow-up interviews were completed in October 2009 on these participants, approximately 18 months after baseline data collection. The baseline and follow-up data were collected as part of a one-time $3.5 million dollar grant administered by the California Community Foundation. The proposed NIMH project would provide funds to enable additional research using this longitudinal data. Specifically, the proposed project will address three broad aims: (1) To document the magnitude of the mental health problems facing individuals previously deployed for OEF/OIF. This objective includes describing the prevalence of mental health problems and the incidence of TBI, as well as documenting the functional impairments and longitudinal trends associated with these problems. (2) To investigate the relationship between PTSD and post-concussive symptoms. Specifically, the research will: (a) determine the extent to which these two types of symptoms are associated with similar trauma types, (b) assess if they have distinct patterns of association with measures of functional impairment, and (c) determine if one type of symptom predicts subsequent changes in the other. (3) To identify the factors that inhibit service utilization for individuals with mental health problems. To address this goal, we will document service members'treatment beliefs and preferences, determine which barriers measured at baseline are associated with subsequent unmet need for services, and identify participants' beliefs about the side-effects of the drugs used to treat PTSD and depression. The proposed research will make a significant contribution to the public health challenges facing the United States. The first two aims are directly responsive to four NIMH program announcements (PA-07-312, PA-07-082, PA-08-255, &PA-08-029). Aim 3 will address the underutilization of treatments, which has been identified by the Department of Defense Task Force on Mental Health as being one of the primary health challenges affecting military service members. Over the next several years, both policy makers and clinicians must make critical decisions affecting individuals injured in OEF/OIF. The proposed project would be in a unique position to improve these decisions. PUBLIC HEALTH RELEVANCE: The proposed project would document rates of mental health problems and possible brain injuries among individuals previously deployed for wars in Iraqi and Afghanistan, and determine if their health is improving over time. The project would also inform treatment decisions for veterans who experience these problems, and would identify ways to encouraging those with mental health problems to get needed care.